Motorized locomotion assisting exoskeleton devices have been proposed for assisting people with disabilities to walk or to perform other tasks. In addition to enabling the performance of the tasks, enabling a person to walk may also impart therapeutic benefits. However, a major difficulty with such devices has been the lack of ability to control such devices in an effective, safe, and intuitive manner.
U.S. Pat. No. 7,153,242 (Goffer) describes an apparatus for enabling a person with handicapped lower limbs to walk. The apparatus attaches to parts of the lower portion of the person's body, possibly up to the torso, and includes motorized means of propelling the parts of the body to which it is attached. The apparatus includes sensors for measuring the angles of the joints, and a sensor for measuring the tilt angles of the upper body. The person using the apparatus selects a mode of operation, such as a gait. Initiation and maintaining of a gait is indicated by the tilt of the upper body of the person using the apparatus. For example, leaning forward triggers a forward step, and swinging the upper body from an upright position to a forward bend maintains a walking gait sequence wherein the apparatus performs the required sequence of movements of the lower limbs, including lifting, extending, bending, and lowering. However, such control by means of measuring the tilt of the upper body may be insufficient. For example, tilting the upper body does not enable the user of the apparatus to indicate with which leg to initiate the gait. Thus, user control is limited. In addition, such an apparatus does not provide control feedback for monitoring the phases and progress of the gait, and cannot alert the user to hazardous situations such as a forbidden arrangement of the feet.
Another powered exoskeleton, called a “hybrid assistive limb” or “HAL,” is described by Boyd in “Bionic suit offers wearers super-strength” (New Scientist, issue 2494, 9 Apr. 2005). Two control methods are described. In the first method described, sensors on the skin detect electric nerve signals from the brain to the leg muscles that indicate intention to move a leg. The device guides movement of the legs in accordance with the user's intentions. In the second described method, sensors detect when the user has started to move. The device then activates itself automatically to augment the power of user's muscles. Neither control method may be used by a paraplegic user whose nerves do not transmit signals from the brain to the legs.
It is an object of the present invention to provide an apparatus and method for controlling a locomotion assisting exoskeleton device in an intuitive and natural manner by a paraplegic or other user, and for providing feedback with regard to performance.
It is a further object of the present invention to provide an apparatus and method for enhancing the safety of a locomotion assisting exoskeleton device.
Other aims and advantages of the present invention will become apparent after reading the present invention and reviewing the accompanying drawings.